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-rw-r--r--src/device/i2c_bus.c37
-rw-r--r--src/include/device/i2c_bus.h8
2 files changed, 45 insertions, 0 deletions
diff --git a/src/device/i2c_bus.c b/src/device/i2c_bus.c
index 30bb80ca98..93634d223b 100644
--- a/src/device/i2c_bus.c
+++ b/src/device/i2c_bus.c
@@ -16,6 +16,7 @@
#include <console/console.h>
#include <device/smbus.h>
#include <device/i2c_bus.h>
+#include <commonlib/endian.h>
struct bus *i2c_link(struct device *const dev)
{
@@ -159,3 +160,39 @@ int i2c_dev_writeb_at(struct device *const dev,
return -1;
}
}
+
+int i2c_dev_read_at16(struct device *const dev,
+ uint8_t *const buf, const size_t len, uint16_t off)
+{
+ struct device *const busdev = i2c_busdev(dev);
+ if (!busdev)
+ return -1;
+
+ if (busdev->ops->ops_i2c_bus) {
+ const struct i2c_msg msg[] = {
+ {
+ .flags = 0,
+ .slave = dev->path.i2c.device,
+ .buf = (uint8_t *)&off,
+ .len = sizeof(off),
+ },
+ {
+ .flags = I2C_M_RD,
+ .slave = dev->path.i2c.device,
+ .buf = buf,
+ .len = len,
+ },
+ };
+
+ write_be16(&off, off);
+ const int ret = busdev->ops->ops_i2c_bus->transfer(
+ busdev, msg, ARRAY_SIZE(msg));
+ if (ret)
+ return ret;
+ else
+ return len;
+ } else {
+ printk(BIOS_ERR, "%s Missing ops_i2c_bus->transfer", dev_path(busdev));
+ return -1;
+ }
+}
diff --git a/src/include/device/i2c_bus.h b/src/include/device/i2c_bus.h
index 6aa4f9ba9d..5302d20228 100644
--- a/src/include/device/i2c_bus.h
+++ b/src/include/device/i2c_bus.h
@@ -89,4 +89,12 @@ int i2c_dev_readb_at(struct device *, uint8_t off);
*/
int i2c_dev_writeb_at(struct device *, uint8_t off, uint8_t val);
+/*
+ * Sends the 16-bit register offset `off` and reads `len` bytes into `buf`.
+ *
+ * Returns the number of bytes read on success, negative `enum cb_err`
+ * value on error.
+ */
+int i2c_dev_read_at16(struct device *, uint8_t *buf, size_t len, uint16_t off);
+
#endif /* _DEVICE_I2C_BUS_H_ */